@type-map-for/clickhouse

Generate ClickHouse table schemas from TypeScript interfaces at compile time with template literal types.

Installation

npm install @type-map-for/clickhouse

Usage

import type { ClickHouseSchema } from '@type-map-for/clickhouse';

interface Event {
  id: string;
  timestamp: number;
  message?: string;
  tags: string[];
  metadata: { source: string };
}

type EventSchema = ClickHouseSchema<Event>;
// Result: Array<{
//   { name: 'id'; type: 'String' }
//   { name: 'timestamp'; type: 'Int32' | 'Float64' }
//   { name: 'message'; type: 'Nullable(String)' }
//   { name: 'tags'; type: 'Array(String)' }
//   { name: 'metadata'; type: 'JSON' }
// }>

// Use with schema validation
const eventSchema: EventSchema = [
  { name: 'id', type: 'String' },
  { name: 'timestamp', type: 'Int32' },
  { name: 'message', type: 'Nullable(String)' },
  { name: 'tags', type: 'Array(String)' },
  { name: 'metadata', type: 'JSON' }
] as const satisfies EventSchema;

Type Mapping

| TypeScript | ClickHouse | |------------|------------| | string | 'String' | | number | 'Int32' | 'Float64' | | boolean | 'Bool' | | object | 'JSON' | | T[] | 'Array(T)' (template literal) | | T \| undefined | 'Nullable(T)' (template literal) |

Types

• ChType<T> - ClickHouse type string for TypeScript type T
• ClickHouseField<T, K> - Schema field for property K of type T
• ClickHouseSchema<T> - Complete schema array for interface T

Contributing

Issues and pull requests welcome at github.com/nathancanine/type-map-for.

License

MIT